1. Field of the Invention
The present invention relates to components for breathing circuits and in particular to components for use in the expiratory arm of a breathing circuit.
2. Summary of the Prior Art
In assisted breathing, particularly in medical applications, gases having high levels of relative humidity are supplied and returned through conduits of a relatively restricted size. Buildup of condensation on the inside wall of the conduit is a frequent result of this high humidity. In the prior art, attempts have been made to reduce the adverse effect of this condensation by either reducing the level of condensation or providing collection points in the conduit for draining condensed liquid from the conduit. Reducing the condensation has generally been by maintaining or elevating the temperature of the gases flow and/or of the conduit wall to reduce the formation of condensation
It is an object of the present invention to provide a component, with particular application to the expiratory limb of a breathing circuit, which will at least go some way towards improving on the above or which will at least provide the public and the medical profession with a useful choice.
In a first aspect the invention consists in a breathing circuit component including an inlet, an outlet and an enclosing wall defining a gases passageway between said inlet and said outlet, at least a region of said wall being of a material that allows the passage of water vapour without allowing the passage of liquid water or respiratory gases.
In a further aspect the invention consists in a breathing circuit limb having both inspiratory and expiratory gases passageways, each having a respective inlet and outlet and a wall defining a gases passageway extending from said inlet to said outlet, at least a region of the wall of the expiratory conduit being of a material that allows the passage of water vapour without allowing the passage of liquid water or respiratory gases.
In a still further aspect the invention consists in a catheter mount including:
a short length of breathing conduit for connecting at one end to a patient interface component and at the other end to, directly or indirectly, the dual arms of a breathing circuit,
a dividing partition extending for at least a substantial part of the length of said breathing conduit and dividing, in cross section, said conduit into a plurality of gases passageways each having a defining passageway wall,
at least one of
an inspiratory flow director for directing at least the bulk of an inspiratory air flow to a first selection of said passageways, and
an expiratory flow director for directing at least the bulk of an expiratory flow to a second selection of said passageways, said second selection being exclusive of said first selection,
and at least a region of the walls of said second selection of passageways being of a material that allows the passage of water vapour without allowing the passage of liquid water or respiratory gases.
In a still further aspect the invention consists in a dedicated water vapour exchanger including an inspiratory gases pathway and an expiratory gases pathway having a common wall therebetween, said common wall including one or more regions of a material that allows the passage of water vapour without allowing the passage of liquid water or respiratory gases.
In a still further aspect the invention consists in apparatus for forming a breathing circuit conduit comprising:
a former, onto which a tube wall can be deposited and which advances said deposited tube wall in an advance axis and rotates said deposited tube wall about said advance direction, the speed of said advance and the speed of said rotation together defining a pitch,
at least one film laying head which deposits a film on said former, the combined width of said film deposited by said film laying heads being wider than said pitch such that adjacent turns of laid film overlap to form an overlap seam,
a bead laying head for each said film laying head, each said bead laying head laying a reinforcing bead on an overlap seam,
an axial thread laying head, said thread laying head fitted over and around said former and carrying a plurality of thread feeds, each thread feed allowing the drawing of a thread from a reserve, and
a rotator to rotate said axial thread laying head at substantially the same speed as the expected rotation speed of said tube.
Hereinafter, throughout the description, a material that allows the passage of water vapour without allowing the passage of liquid water or respiratory gases is described as a xe2x80x9cbreathablexe2x80x9d material. Materials may be breathable due to their composition, physical structure a combination thereof.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.